Pilfer-resistant lock construction, having segmented cylinder

ABSTRACT

A pilfer resistant lock construction characterized in the provision of a longitudinally segmented cylinder, each segment supporting a laterally shiftable tumbler. Each segment is separated from the other segments by a small ball seated in a pair of opposed corresponding detents. The balls remain in position under normal keyed operation. However, if an attempt is made to pick the lock, one tumbler at a time, the segments rotate axially with respect to each other, causing the balls to rotate out of the respective detents, resulting in longitudinal expansion of the space between the segments against the action of a longitudinally arranged spring. This expansion causes a locking action between the cylinder and a member which is non-rotatably fixed with respect to the lock housing, and prevents rotation of the cylinder within the lock. The forwardmost cylinder segment is devoid of a tumbler, and is free turning, to discourage attempts to drill out the cylinder, by rotating with the drill bit.

'[76] Inventor:

United States Patent [191 Mercurio PILFER-RESISTANT LOCK CONSTRUCTION, HAVING SEGMENTED CYLINDER [52] US. Cl. 70/419, 70/375 [51] Int. Cl E05b 63/00 [58] Field of Search 70/419, 375, 373, 416

[56] References Cited UNITED STATES PATENTS 3,500,670 3/1970 Hawkins 70/375 Primary Examiner-Robert L. Wolfe Attorney, Agent, or F irmCharles E. Temko 57 ABSTRACT A pilfer resistant lock construction characterized in [451 May 7,1974

the provision of a longitudinally segmented cylinder, each segment supporting a laterally shiftable tumbler. Each segment is separated from the other segments by a small ball seated in a pair of opposed corresponding detents. The balls remain in position under normal keyed operation. However, if an attempt is made to pick the lock, one tumbler at a time, the segments rotate axially with respect to each other, causing the balls to rotate out of the respective detents, resulting in longitudinal expansion of the space between the segments against the action of a longitudinally arranged spring. This expansion causes a locking action between the cylinder and a member which is nonrotatably fixed with respect to the lock housing, and prevents rotation of the cylinder within the lock. The

forwardmost cylinder segment is devoid of a tumbler,

and is free turning, to discourage attempts to drill out the cylinder, by rotating with the drill bit.

4 Claims, 10 Drawing Figures PATENTEDHAY H914 FIGS FIG.2

I M m FIG.5

FIG.4

FIG. 9

PILFER-RESISTANT LOCK CONSTRUCTION,

HAVING SEGMENTED CYLINDER This invention relates generally to the field of tumbler locks, and more particularly to an improved form having secondary locking means to improve its pickresistant properties. Locks of this type are generally known in the art, and the invention lies in specific constructional details of construction. Reference is made to my co-pending application, Ser. No. 275,770; filed July 27, 19 7 2, which discloses and claims somewhat related structure.

BRIEF DESCRIPTION OF THE PRIOR ART Devices of this general type are'principally employed for the locking of coin vaults associated with coin operated devices of various types, such as laundry appliances, amusement games, vending machines and the like. Such locks are characterized in the provision of unusual location of the tumblers, i.e. with the axis parallel to the axis of rotation of the cylinder, or by the provision of secondary locking means which will render the lock inoperative if an attempt is made to open the same using a pick or other tool, rather than the key corresponding to the individual tumblers. A standing requirement in the'art is the development of new look constructions to replace those, the structure of which has been learned by professional thieves, and which are readily defeated by them with continued experience.

BRIEF DESCRIPTION OF THE PRESENT INVENTION Briefly stated, the invention contemplates the provision of an improved cylinder lock construction, in which the cylinder, instead of being made from a unitary piece of metal, and containing a plurality of tumblers, is segmented to include a plurality of cylindrical segments, each supporting one tumbler, so that it becomes impossible to pick the look by the traditional method, one tumbler at a time accompanied by slight additional rotation of the cylinder within the housing with each tumbler overcome. Secondary locking means is provided in the form of longitudinally arranged pins engaging corresponding openings in structure fixed with respective lock housing, this structure being actuated by relative rotation between the lock cylinder segments, should the pilferer succeed in overcoming one or more tumblers. This longitudinal expansion of the cylinder element is accomplished by providing hemispherical detents in the abutting surfaces of the cylinder segments accommodating a small ball which is rolled from the detents upon the occurrence of relative movement between adjacent cylinder segments, each ball increasing the effective length of the cylinder by the diameter of the ball.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, to which reference will be made in the specification, similar reference characters have been employed to designate corresponding parts throughout the several views.

FIG. 1 is a side elevational view of an embodiment of the invention, partly broken away to show detail.

FIG. 2 is a front end elevational view thereof.

FIG. 3 is a rear end elevational view thereof.

8 sleeve shown in FIGS. 4 and 5.

FIG. 8 is a side elevational view of a cylindrical plug forming part of a secondary locking means.

FIG. 9 is an exploded view in elevation showing the alignment of a plurality of cylinder segments.

FIG. 10 is a view in elevation of a locking plate forming a part of a secondary locking structure.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENT able structure (not shown) in non-rotatable relation.

Extending through the entire axial length of the element is a longitudinal bore 19 of generally cylindrical configuration, and having first and second longitudinal grooves 20 and 21, respectively, extending radially therefrom. A circular groove 22 provides means for the seating of a snap ring 23 which operates with a transversely extending shoulder 24 to maintain the device in assembled condition.

The cylinder element 12 includes a pin-bearing plug 25 which forms part of the secondary locking means 13, a first cylinder segment 26 which is devoid of tumbler structure, second, third, fourth and fifth cylinder segments27, 28, 29 and 30, respectively, and a cylinder sleeve member 31.

The first cylinder segment includes first and second planar surfaces 32-33 and a peripheral surface 34, permitting the same to turn within the sleeve member 31, not only upon engagement of a key (not shown) but upon engagement of the surface 32 with a drill bit, should an attempt be made to drill out the cylinder.

Thus, the first segment will tend to turn with the drill bit, thus preventing a cutting action to occur.

The second, third, fourth and fifth cylinder segments 27-30 are generally similar, each' including an outer planar surface 35, an inner planar surface 36 and a laterally extending groove 37 supporting a slidably mounted planar tumbler 38. Each of the tumblers includes a lug 39 coacting with a spring 40 tending to urge the tumbler radially outwardly to engage one of the grooves 20-21 in the absence of an engaged key shank (see FIG. 6). Each of the planar surfaces 35-36 includes an aligned hemispherical recess 41 accommodating one half of a'small ball 42, so that when the opposed recesses in adjoining cylinder segments are aligned, the ball is completely enclosed, and the planar the balls 42 will become unseated, and tend to ride up the sides of the recesses 41 which operate as detents, thus spacing the segments longitudinally by the diameter of the ball as they contact the planar surfaces surrounding the recesses.

The plug 25 includes a cylindrical member 45 bounded by an outer surface 46 and an inner surface 47. A cylindrical surface 48 corresponds in diameter to that of the segments 26-30. The outer surface 46 includes a slot 49 for the insertion of pins 50 force fitted within corresponding bores (not shown). A centrally disposed shaft extends rearwardly from the inner surface 47, and contacts a spring 52 supported by the sleeve member 31.

The sleeve member 31 includes a hollow shell 55 having a cylindrical wall 56 bounded by an outer surface 57 and an inner surface 58. A pair of elongated slots 59 and 60 correspond in location to the grooves 20-2l, and permit egress of the tumblers 38 in either of two rotational positions. A rear wall 61 contains a central opening 62 leading to a hollow shaft 63 supporting the above mentioned spring 52 and accommodating the shaft 51 slidably therein. Peripheral holes 64 selectively accommodate the pins 50 when the plug 25 is displaced rearwardly.

The secondary locking means 13 includes the plug 25, and a corresponding locking plate 66 (FIG. the

. plate having a central opening 67 to enable it to be fitted upon the shaft 63, and a pair of radially extending projections 68 and 69 engaging the grooves -21 to prevent relative rotation between the plate 66 and the housing element 11.

During operation, upon the insertion of a key (not shown), the tumblers 38 will be aligned in normal manner to permit rotation of the cylinder element 12 as a unit with respect to the housing element 11. Should an attempt be made to open the lock by unauthorized means, depending upon the methods employed, various constructional aspects of the lock will prevent opening. As mentioned hereinabove, an attempt to drill out the cylinder will result in free rotation of the first cylinder segment 26, making the drilling operation extremely difficult, if not impossible. If an attempt is made to pick the lock, tumbler by tumbler, the wedge shaped configuration of the tumblers engaged within the wedge shaped corresponding configuration of the grooves 20-21 makes it difficult to pull the tumblers down once a small degree of initial rotation necessarily accompanying this procedure has been made. Should this be overcome, the second cylinder segment turning freely will expand the effective length of the entire cylinder, causing the plug 25 to be moved rearwardly to a point where the pins 50 engage the openings in the plate 66,-thus operating the secondary locking means. If the rotated segment is returned to its initial position, the lock is returned to status quo, without damage, and an authorized person may employ the proper key in normal manner.

I wish it to be understood that I do not consider the invention limited to the precise details of structure shown and set forth in this specification, for obvious modifications will occur to those skilled in the art to which the invention pertains.

I claim:

1. A cylinder lock construction comprising: a housing element, a longitudinally segmented cylinder element having a principal axis disposed within said housing element and having tumblers selectively laterally extendable to engage fixed surfaces on said housing element, means in each of said segments for receiving a key to align the tumblers thereof for simultaneous rotation between locking and unlocking positions; said tumblers being capable of independent axial rotation in the absence of a key, and means axially responsive to said independent rotation serving to lock said cylinder element relative to said housing element to prevent relative rotation; each of said cylinder segments normally abutting adjacent segments, and having therebetween a small ball received in a corresponding hemispherically-shaped detent in each of two abutting surfaces, said ball being disengaged upon relative rotation of abutting cylinder segments to operate said axially-responsive means.

2. Structure in accordance with claim 1, including a forwardmost cylinder segment capable of free rotation within said housing element and independent of the remaining cylinder segments for the purpose of discouraging attempts to drill out said cylinder segments.

3. Structure in accordance with claim 1, said axiallyresponsive means including a rotatable plug abutting the inwardmost of said cylinder segments, and having at least one longitudinally aligned pin extending therefrom; and a foraminous member fixed against rotational movement relative to said housing into which said pin is selectively projected.

4. Structure in accordance with claim 3, including resilient means urging said plug out of engagement with said fixed member.

* l II! 

1. A cylinder lock construction comprising: a housing element, a longitudinally segmented cylinder element having a principal axis disposed within said housing element and having tumblers selectively laterally extendable to engage fixed surfaces on said housing element, means in each of said segments for receiving a key to align the tumblers thereof for simultaneous rotation between locking and unlocking positions; said tumblers being capable of independent axial rotation in the absence of a key, and means axially responsive to said independent rotation serving to lock said cylinder element relative to said housing element to prevent relative rotation; each of said cylinder segments normally abutting adjacent segments, and having therebetween a small ball received in a corresponding hemispherically-shaped detent in each of two abutting surfaces, said ball being disengaged upon relative rotation of abutting cylinder segments to operate said axially-responsive means.
 2. Structure in accordance with claim 1, including a forwardmost cylinder segment capable of free rotatiOn within said housing element and independent of the remaining cylinder segments for the purpose of discouraging attempts to drill out said cylinder segments.
 3. Structure in accordance with claim 1, said axially-responsive means including a rotatable plug abutting the inwardmost of said cylinder segments, and having at least one longitudinally aligned pin extending therefrom; and a foraminous member fixed against rotational movement relative to said housing into which said pin is selectively projected.
 4. Structure in accordance with claim 3, including resilient means urging said plug out of engagement with said fixed member. 